1. Technical Field
The present application relates generally to an improved data processing system and method. More specifically, the present application is directed to a power grid structure to optimize performance of a multiple core processor.
2. Description of Related Art
In the early days of computing, engineers and designers were not concerned about how much power a processor used. Early processors had a single voltage level that was used by the motherboard and processor, typically 5 volts.
The amount of voltage is proportional to the amount of power used. Power consumption equates largely with heat generation, which is a primary enemy in achieving increased performance. With a growing number of computers in use, energy conservation has become an issue in computer design. Thus, as processors have increased in speed and size, designers have become more and more concerned about the amount of power being consumed. The first step to solve this concern was to reduce the voltage level to 3.3 volts.
Newer processors reduce voltage levels even more by using what is called a “dual voltage” or “split rail” design. A split rail uses two different voltages. The external or I/O voltage is higher, typically 3.3 volts, for compatibility with the other chips on the motherboard. The internal or “core voltage” is lower, usually 1.0 to 2.9 volts.
Multiple core processors complicate the issue of power consumption even further. The term “core” typically refers to a relatively large, general-purpose logic function that is used as a building block in a chip design. In a microprocessor, a central processing unit (CPU), or “processor.” A multiple core processor has a plurality of processors. Within the context of this disclosure, a multiple core processor may also be referred to as a “system on a chip.” In microprocessor design, processor manufacturers try to solve the concern about power consumption by using lower-power semiconductor processes and shrinking the die size, while still adding more and more functionality to the chip. As the die size shrinks and more components, such as processor cores, are packed into the processor design, variability in fabrication has a greater impact on performance and power consumption.